武汉地铁6号线岩溶发育特征及治理方案比选

Characteristics of Karst Development and Karst Treatments of Wuhan Metro Line 6

基于岩溶专项勘察资料,通过数学统计方法分析研究区岩溶发育特征。根据上覆盖土层和基岩之间的组合关系将岩溶地质结构分为两大类,并结合岩溶发育特征提出对应治理方案。运用数值模拟手段研究岩溶塌陷发生时,I类岩溶地质结构治理方案中两种不同类型的隔离桩的受力情况。研究结果表明,研究区岩溶主要发育于基岩面以下15 m范围内,以垂向发育形态为主。绝大部分溶洞高度小于3 m,充填形式以全充填为主。岩溶治理方案由帷幕注浆、区间满铺注浆、隔离桩及溶洞注浆等措施组成,其中B型隔离桩(单排旋喷桩+单排灌注桩)的受力特性优于A型隔离桩(三排旋喷桩),建议优先采用。

The characteristics of karst development in study area are analyzed by mathematical and statistical methods based on the karst investigation data.Meanwhile,the karst geological structures are classified into two types according to combination relation between overlying soil layers and bedrock,and the karst treatments are proposed considering the characteristics of karst development.The stress distributions of two different types of partition piles of the treatment for type I karst geological structure are investigated by means of numerical simulation.The results indicate that the most of karst caves develops along the vertical direction within the scope of 0 ~ 15 m below the rock surface.The height of the majority of karst caves is less than 3 m and the most common filling type of karst caves is full filling.The karst treatments consist of curtain grouting,full grouting in the section,partition piles and grouting for karst caves.The type B partition pile,which is comprised of a row of jet grouting piles and a row of bored piles,is suggested to be adopted preferentially because its mechanical behavior is better than the type A partition pile composed of three rows of jet grouting piles.